Browsing by Author "Kumar, C.V. Sameer"

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    Characterization and mapping of Dt1 locus which co‑segregates with CcTFL1 for growth habit in pigeonpea
    (Theor Appl Genet, 2017) Saxena, Rachit K; Obala, Jimmy; Sinjushin, Andrey; Kumar, C.V. Sameer; Saxena, K.B.; Varshney, Rajeev K.
    Pigeonpea (Cajanus cajan) is one of the most important legume crops grown in arid and semi-arid regions of the world. It is characterized with few unique features compared with other legume species, such as Lotus, Med icago, and Glycine. One of them is growth habit, an impor tant agronomic trait. In the present study, identifcation of mutations affecting growth habit accompanied by a pre cise analysis of phenotype has been done which will shed more light upon developmental regulation in pigeonpea. A genetic study was conducted to examine the inheritance of growth habit and a genotyping by sequencing (GBS)-based genetic map constructed using F2 mapping population derived from crossing parents ICP 5529 and ICP 11605. Inheritance studies clearly demonstrated the dominance of indeterminate (IDT) growth habit over determinate (DT) growth habit in F2 and F2:3 progenies. A total of 787 SNP markers were mapped in the genetic map of 1454 cM map length. Growth habit locus (Dt1) was mapped on the CcLG03 contributing more than 61% of total phenotypic variations. Subsequently, QTL analysis highlighted one gene, CcTFL1, as a candidate for determinacy in pigeon pea, since an Indel marker derived from this gene co-seg regated with the Dt1 locus. Ability of this Indel-derived marker to differentiate DT/IDT lines was also validated on 262 pigeonpea lines. This study clearly demonstrated that CcTFL1 is a candidate gene for growth habit in pigeonpea and a user-friendly marker was developed in the present study which will allow low-cost genotyping without need of automation.
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    Seed protein content and its relationships with agronomic traits in pigeonpea is controlled by both main and epistatic efects QTLs
    (Scientific Reports, 2020) Obala, Jimmy; Saxena, Rachit K.; Singh, Vikas K.; Kale, Sandip M.; Garg, Vanika; Kumar, C.V. Sameer; Saxena, K. B.; Tongoona, Pangirayi; Sibiya, Julia; Varshney, Rajeev K.
    The genetic architecture of seed protein content (SPC) and its relationships to agronomic traits in pigeonpea is poorly understood. Accordingly, fve F2 populations segregating for SPC and four agronomic traits (seed weight (SW), seed yield (SY), growth habit (GH) and days to frst fowering (DFF)) were phenotyped and genotyped using genotyping-by-sequencing approach. Five high-density population-specifc genetic maps were constructed with an average inter-marker distance of 1.6 to 3.5cM, and subsequently, integrated into a consensus map with average marker spacing of 1.6cM. Based on analysis of phenotyping data and genotyping data, 192 main efect QTLs (M-QTLs) with phenotypic variation explained (PVE) of 0.7 to 91.3% were detected for the fve traits across the fve populations. Major efect (PVE≥10%) M-QTLs included 14 M-QTLs for SPC, 16 M-QTLs for SW, 17 M-QTLs for SY, 19 M-QTLs for GH and 24 M-QTLs for DFF. Also, 573 epistatic QTLs (E-QTLs) were detected with PVE ranging from 6.3 to 99.4% across traits and populations. Colocalization of M-QTLs and E-QTLs explained the genetic basis of the signifcant (P<0.05) correlations of SPC with SW, SY, DFF and GH. The nature of genetic architecture of SPC and its relationship with agronomic traits suggest that genomics-assisted breeding targeting genome-wide variations would be efective for the simultaneous improvement of SPC and other important traits.